Carrier billing lets you buy apps, games, or digital services and have the cost...

https://www.bookmarkidea.win/carrier-billing-lets-you-buy-apps-games-or-other-digital-content-and-charge

Carrier billing lets you buy apps, games, or digital services and have the cost added directly to your monthly phone bill. If you use a pay-as-you-go plan, the purchase amount is taken from your prepaid credit